Assuming the FTP Virtual server has been configured already, setup access to a new site as follows:
- Under the settings for the Web Server (Root node) select IIS Manager Users and create and enable a new user.
- Under the Root FTP Site (Virtual Server) select IIS Manager Permissions and add the user you created in the previous step.
- Create a virtual directory under the Root FTP site/LocalUser for the user (must match username).
- Click on the created virtual directory and in the right pane select FTP Authorization Rules and add the user with Read/Write permissions.